Has Stack Overflow an overall positive impact on programmers productivity?

On one side, it takes time and effort to ask and answer questions -- thus decreasing productivity.

On the other side, more and more programmer questions are answered and easily found through Google. This allows many programmers to find solutions to their problems quicker than ever before, thus increasing productivity.

Has Stack Overflow been economically beneficial to programmer productivity? If so, can this be quantified in terms of money?

Note: I've asked this related question on Skeptics.SE, but it turns out there is no peer-reviewed research on the matter.

Has Stack Overflow an overall positive impact on programmers productivity?

On one side, it takes time and effort to ask and answer questions -- thus decreasing productivity.

On the other side, more and more programmer questions are answered and easily found through Google. This allows many programmers to find solutions to their problems quicker than ever before, thus increasing productivity.

Has Stack Overflow been economically beneficial to programmer productivity? If so, can this be quantified in terms of money?

Note: I've asked this related question on Skeptics.SE, but it turns out there is no peer-reviewed research on the matter.